Why doesn't Shang Ceng want anyone from Xingjie Project?

Shang Ceng doesn't want anyone from Xingjie Project because they are in the same industry. Xingjie and Shangceng are both decoration companies, both of whom are peers and have a certain reputation in Shanghai. One of the reasons for not recruiting peers is that peers know too much inside information, which is difficult to manage, and the other is that people who quit their jobs will not last long.